The present invention relates to a method for decoding a convolutionally coded input data signal y comprising multiplying the input data signal with a scaling factor Lc, demultiplexing the multiplied input data signal Lcy into three signals which are related to systematic bits and parity bits, a demultiplexed input data signal LcS being associated with the systematic bits, e.g. in parity signals and a systematic signal and turbo decoding the demultiplexed input data signal LcS in order to obtain turbo decoded output Λ. In a further aspect, the present invention relates to a decoder device for decoding a convolutionally coded input data signal y comprising a multiplication element for multiplying a received input data signal y with a scaling factor L, a demultiplexer for demultiplexing the multiplied input data signal ly, e.g. in parity signals and a systematic signal, and a turbo decoder for decoding the demultiplexed input data signal IS in order to obtain decoder output likelihood ratio data.